'YOU S---': Cameron has to stop this today or he will lose control

Dean Mouhtaropoulos/Getty Images On Friday evening former Tory leader Iain Duncan Smith resigned from his position as Work and Pensions secretary and plunged his party into crisis. IDS, as he is universally known, said he was stepping down because the cuts announced to benefits for disabled people by George Osborne in the budget were "unfair."

In an attempt to take control of the situation, Prime Minister David Cameron will almost certainly use a statement today about last week's EU summit to try and defend the Government's record, and to convince his party members to stop stabbing each other in the back.

Here's why it's so important that Cameron wrestles back control of the situation.

Cameron tells IDS, "you s---"

Everything kicked off around 9 p.m. on Friday. Cameron had been trying to persuade IDS to stay, but when it became clear that he was going to resign, Cameron is reported to have lost his temper. Both the Mail and the Times say that the Prime Minister swore at IDS, saying "you shit" and calling him dishonourable.

We can't know for sure what was said during that phone call, but IDS wasn't in a mood to hold anything back this weekend. He told the BBC's Andrew Marr show on Sunday that the Government was in "danger of drifting in a direction that divides society rather than unites it. And that I think is unfair."

That was read by Conservatives as a direct attack on Cameron as a Prime Minister.

Cameron has tried to turn the Tories into a "One Nation" party, which fights for everyone in society regardless of their economic circumstances. The fact that his own welfare secretary is saying that he has failed is potentially damaging to Cameron.

On the Prime Minister's side, the attack against IDS has been two-pronged. IDS has been accused of having ulterior motives, resigning because he wants to damage the Prime Minister in the run-up to the EU referendum vote. IDS backs a Brexit, while Cameron wants Britain to remain in the EU.

There has also been some very strong briefing against IDS, presumably sanctioned by Downing Street. In an extraordinary letter, a pensions minister called Ros Altmann accused her now former boss IDS of planning his resignation in order "to do maximum damage to the party leadership."

None of this looks good for Osborne

The viciousness of the attacks on both sides has allowed the story to run out of control. Yesterday, the Sunday Times, the Sunday Telegraph and the Mail on Sunday were all speculating that IDS's resignation had basically ended Osborne's ambitions of becoming Prime Minister, because it suggests that Osborne doesn't have credibility with senior party figures.

The Financial Times reported on Sunday that the disability cut ended up in the budget almost by accident: The Conservatives did not expect to win the last election unless they were in a coalition with the Liberal Democrats, and Osborne expected the Lib-Dems to demand the cuts be lessened. In the event, the Tories won outright, locking Osborne into a plan that had sounded good as an election promise but was radioactive as an actual policy.

Today the Times is reporting that Cameron has told a cabinet colleague that he blames Osborne for screwing up the budget and causing a row over disability cuts that was completely unnecessary. This is what they quote a source as saying:

Cameron said in no uncertain terms that Osborne had messed up, it was all his fault and would have hell to pay in the papers.

Whether this is true or not, in less than 24 hours the story has moved from "Osborne's leadership chances are over," to "the Prime Minister is losing confidence in the man he trusts to run the country's finances."

The new leader of the opposition

The joke is that the Labour party is so rubbish at the moment that IDS has had to step in to do its job for them. It's not too far from the truth. Ever since they won the election, the government has been cruising and hasn't faced any meaningful threat from the opposition. Now, with the EU referendum approaching, the government faces a much scarier threat than Jeremy Corbyn - their own side.

Cameron needs to put a stop to all this today, or he genuinely faces watching his government fall apart.